1. Field of the Invention
The present invention relates to a motor vehicle equipped with a so-called xe2x80x9chands-freexe2x80x9d access system.
2. Description of Related Art
In such a system, an identification device is installed on the vehicle, to control the means for locking the opening leaves of the vehicle, this identification device being capable of remotely exchanging data with an identifier worn or carried by a user, so as to allow access to the vehicle when the identifier has been authenticated by the identification device. To allow dialog between the identification device and the identifier, a number of antennas are distributed around the periphery of the vehicle, so as to detect the presence of the identifier. Such antennas are, for example, arranged in the rear-view mirror, the door handles and the door uprights. When the identifier is moved away from the area of coverage of said external antennas, the system automatically locks the opening leaves of the vehicle.
Furthermore, these systems may control the starting of the engine of the vehicle, when a person authorized to drive the vehicle is inside the cabin. In this case, antennas are arranged, for example, on the instrument panel, in the seats of the vehicle or on the interior walls of the doors.
However, the number of antennas to be installed on the vehicle has become great, increasing the cost and time involved in mounting the system on the vehicle.
Incidentally, the present applicant company has, in document FR-A-2 740 501, described a xe2x80x9chands-freexe2x80x9d access system in which two antennas are arranged at the rear of the vehicle, in the region of the trunk, so that the areas of coverage of the two rear antennas have little or no overlap, so that the transponder worn or carried by a user can dialog with just one antenna at a time. The unlocking of the lid to the trunk is commanded when the transponder is presented to the two rear antennas of the vehicle in a predetermined sequence.
The object of the invention is to eliminate the aforementioned drawbacks and provide a motor vehicle equipped with a xe2x80x9chands-freexe2x80x9d access system in which the number of antennas needed is lower, while at the same time having correct coverage of the vehicle environment.
To this end, the subject of the invention is a motor vehicle equipped with an identification device for controlling means for locking the opening leaves of the vehicle, said identification device being capable of remotely exchanging data with an identifier worn or carried by a user, so as to allow access to the vehicle when the identifier has been authenticated by the identification device, the latter being connected to a number of external antennas on the vehicle so as to allow dialog between the identification device and the identifier, when the latter is positioned in the area of coverage of said antennas, wherein at least one pair of said external antennas comprises a common area of overlap, so that the identification device is able to detect the presence of an identifier in said common area of overlap when said pair of antennas receives a signal from the same identifier, each antenna of said pair of antennas also comprising its own area of coverage without any mutual overlap, so that the identification device is capable of detecting the presence of an identifier in one of the two aforementioned areas of coverage when the associated antenna receives only a signal from the identifier.
Advantageously, the two antennas of each pair are arranged one on each opposite side of the vehicle, so that each antenna has its own area of coverage extending over one of the two sides of the vehicle so that the identification device is able to detect the presence of the identifier in proximity to a door located on one of the two sides of the vehicle, so as to control means for locking the doors. As a preference, the antennas of said pair are arranged symmetrically with respect to the longitudinal axis of the vehicle.
In a first embodiment, a pair of antennas is arranged at the rear of the vehicle, so that the common area of overlap extends toward the rear of the trunk lid, detection of an identifier in said common area of overlap, by the two antennas, being intended to control locking/unlocking the trunk lid only.
By way of example, said pair of antennas may be installed in the rear bumper, the rear lights, or the rear side moldings of the vehicle.
In another embodiment, one pair of antennas is arranged practically in the middle of the sides of the vehicle, so that the common area of overlap extends inside the cabin of the vehicle, so as to allow the identification device to detect the presence of an identifier in the cabin so as, for example, to control the inhibiting of a means for preventing the vehicle from being started.
Advantageously, said pair of antennas is installed in the handles of doors or in the door surround pillars.
In general, the external antennas are intended to emit at low frequency, for example at 125 kHz, whereas the identifiers are capable of responding by emitting in radio frequency, for example at 434 MHz.